Infant nasal interface mask

ABSTRACT

An infant nasal interface mask for use with a nasal continuous positive airway pressure (nCPAP) system including a mask body and a base. The mask body forms a cavity and is defined by a leading portion, an intermediate shell portion, and a trailing portion. The leading portion terminates in a leading edge forming an aperture open to the cavity and having a generally triangular shape for placement over a patient&#39;s nose. The trailing portion includes a bellows segment characterized by an increased flexibility as compared to a flexibility of the intermediate shell portion. The base extends from the trailing portion opposite the leading portion and forms at least one longitudinal passage extending through a thickness of the base and fluidly connected to the cavity. The intermediate shell portion is laterally pivotable relative to the base via the bellows segment.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/819,549, filed Jun. 21, 2010, entitled “Infant NasalInterface Mask”, which is a continuation of Ser. No. 11/292,784, filedon Dec. 2, 2005, now U.S. Pat. No. 7,762,258, entitled “Infant NasalInterface Mask”, the contents of which are incorporated herein byreference and for all purposes.

BACKGROUND

The present invention relates to nasal masks for use with continuouspositive airway pressure (CPAP) systems. More particularly, it relatesto a mask worn over the nose of a patient, such as an infant, whenreceiving nasal CPAP therapy.

Continuous positive airway pressure (CPAP) therapy has been employed formany years to treat patients experiencing respiratory difficultiesand/or insufficiencies. More recently, CPAP therapy has been advanced asbeing useful in assisting patients with under-developed lungs (inparticular, infants and especially premature infants or neonates), bypreventing lung collapse during exhalation and assisting lung expansionduring inhalation.

In general terms, CPAP therapy entails the continuous transmission ofpositive pressure into the lungs of a spontaneously breathing patientthroughout the respiratory cycle. A CPAP system generally includes aCPAP generator adapted to create or generate a continuous positiveairway pressure within one or two tubes, along with a patient interfacedevice connected to the generator that serves as a conduit for transferof inhaled and exhaled gases. The CPAP system can assume a variety offorms, including a fixed flow, ventilator-type system, or a variableflow system.

CPAP can be delivered to the patient using a variety of patientinterface devices, for example an endotracheal tube. With infants,however, it is more desirable to employ a less invasive patientinterface device, in particular one that interfaces directly orindirectly with the nasal airways via the patient's nares. Such systemsare commonly referred to as nasal continuous positive airway pressure(nCPAP) systems.

With nCPAP systems, the patient interface piece is typically either adual prong body or a mask. The dual prong device includes two prongs orcannulas each sized for insertion within a respective nare of thepatient. While a relatively stable fluid seal can readily beaccomplished between the prongs and the nasal airways, some patients,especially infants, negatively react to the discomfort attendant withinsertion of the prongs. Conversely, the nasal mask device is placedover the patient's nose and thus, in theory, will cause less patientdiscomfort. Unfortunately, currently available infant nCPAP masks haveseveral shortcomings.

For example, available nCPAP masks are only somewhat flexible(especially relative to a point of interface with the CPAP system) andthus cannot accommodate any misalignment of the nCPAP generator relativeto the patient's nose. When the nCPAP generator is later moved relativeto the patient to correct this misalignment, the nCPAP mask will alsomove in a similar fashion, potentially leading to air leaks relative tothe patient's face or general patient discomfort. This can be especiallyproblematic with infants whom otherwise have small facial features andthus less available surface area for achieving and maintaining a fluidtight seal with the mask.

Along these same lines, it is oftentimes necessary to apply a fairlysignificant force to the nasal mask to ensure a fluid tight seal againstthe patient's nose/face. For example, a strap is commonly wrapped aboutthe patient's head and connected to the CPAP generator. The CPAPgenerator, in turn, is assembled to the nasal mask such that a forceplaced on the CPAP generator by the strap is transferred onto the nasalmask in sealing the mask about the patient's nose. Because theconventional nasal mask may not readily conform to the contours of thepatient's facial anatomy, the strap must be pulled tight so as tomaintain the desired, fluid-tight seal. For certain patients, especiallyinfants, this securing force can cause great discomfort, cause bruisingand lead to skin necrosis. Also, the forces may be concentrated by themask at a few pressure points on the patient's nose/face, furtherincreasing the likelihood of long-term complications (e.g., sores orwounds on the patient's nasal septum, upper lip, nasal bridge, cheeks,etc.). Along these same lines, perhaps in an effort to promote completecontact with the patient's face, conventional nasal mask designsintimately contact the patient's upper lip directly at and below thenasal septum exterior. For many infants, the skin of the upper lipphiltrum is delicate and highly sensitive, and can more easily succumbto necrosis when contacted by the mask. Regardless, an infant patientwill react quite negatively to even minor discomfort associated withapplication of the nasal mask to his or her nose/face.

In light of the above, a need exists for an improved nasal mask for usewith an nCPAP system, especially for infant patient applications.

SUMMARY

Some aspects in accordance with principles of the present inventionrelate to an infant nasal interface mask for use with a nasal continuouspositive airway pressure (nCPAP) system. The mask includes a mask bodyand a base. The mask body forms a cavity and is defined by a leadingportion, an intermediate shell portion, and a trailing portion. In thisregard, the leading portion terminates in a leading edge forming anaperture open to the cavity and having a generally triangular shape forplacement over a patient's nose. Further, the trailing portion includesa bellows segment characterized by an increased flexibility as comparedto a flexibility of the intermediate shell portion. The base extendsfrom the trailing portion opposite the leading portion and forms atleast one longitudinal passage extending through a thickness of the baseand fluidly connected to the cavity. With this in mind, the intermediateshell portion is laterally pivotable relative to the base via thebellows segment. In one embodiment, the trailing portion forms thebellows segment to have a reduced wall thickness as compared to a wallthickness of the intermediate shell portion. In other embodiments, theleading portion forms a patient contact face defining one or morecontours providing for septum and/or ocular relief.

Other aspects in accordance with principles of the present inventionrelate to an infant nasal continuous positive airway pressure (nCPAP)device for use in an nCPAP system. The device includes an nCPAPgenerator and an infant nasal mask. The nCPAP generator includes firstand second tubes fluidly connected to a fluid supply port, with thegenerator adapted to generate a continuous positive airway pressurewithin each of the tubes. The infant nasal mask is mounted to the tubesand includes a mask body and a base. The mask body forms a cavity and isdefined by a leading portion, an intermediate shell portion, and atrailing portion. The leading portion terminates in a leading edgeforming an aperture otherwise open to the cavity and having a generallytriangular shape for placement over a patient's nose. The trailingportion includes a bellows segment characterized by an increasedflexibility as compared to a flexibility of the intermediate shellportion. The base extends from the trailing portion opposite the leadingportion and forms first and second passages extending longitudinallythrough a thickness of the base and fluidly connected to the cavity. Inthis regard, the passages are sized for assembly over a respective oneof the tubes. In one embodiment, upon final assembly, the device isconfigured such that the intermediate shell portion is laterallypivotable relative to both the base and the tubes in a multiplicity ofdirections. In another embodiment, the nCPAP generator further includesa housing laterally surrounding the tube and sized to receive the base.Further, the base and the housing define corresponding, non-symmetricalperimeter shapes such that the base can only be assembled within thehousing in a single orientation.

Yet other aspects in accordance with principles of the present inventionrelate to an infant nasal interface mask for use with an nCPAP system.The mask includes a mask body and a base. The mask body forms a cavitydefined by a leading portion, an intermediate shell portion, and atrailing portion. The leading portion forms a patient contact faceterminating in a leading edge otherwise forming an aperture open to thecavity. The aperture has a generally triangular shape for placement overa patient's nose. Further, the patient contact face has a reduced wallthickness as compared to a nominal wall thickness of the intermediateshell portion and defines opposing ocular reliefs and a septal relieffeature. The trailing portion forms a bellows segment characterized by areduced wall thickness as compared to a nominal wall thickness of theintermediate shell portion, along with a lateral bend in longitudinalextension. The base extends from the trailing portion opposite theleading portion and forms at least one longitudinal passage extendingthrough a thickness of the base and fluidly connected to the cavity.With this in mind, the intermediate shell portion is laterally pivotablerelative to the base via the bellows segment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front perspective view of an infant nasal interface mask inaccordance with principles of the present invention;

FIG. 1B is a rear perspective view of the mask of FIG. 1A;

FIG. 2 is a longitudinal cross-sectional view of the mask of FIG. 1A;

FIG. 3 is a front view of the mask of FIG. 1A;

FIG. 4 is a bottom view of the mask of FIG. 1A;

FIG. 5 is a rear view of the mask of FIG. 1A;

FIG. 6 is a transverse cross-sectional view of the mask of FIG. 1A;

FIG. 7A is an exploded, perspective view of an nCPAP device inaccordance with principles of the present invention including the maskof FIG. 1A and an nCPAP generator;

FIG. 7B is a cross-sectional view of the nCPAP device of FIG. 7A uponfinal assembly; and

FIG. 8 is a side longitudinal cross-section view of an alternativeembodiment infant nasal interface mask in accordance with principles ofthe present invention.

DETAILED DESCRIPTION

One embodiment of an infant nasal interface mask 20 for use with a nasalcontinuous positive airway pressure (nCPAP) system is shown in FIGS. 1Aand 1B. The mask 20 includes a mask body 22 and a base 24. The mask body22 forms an internal cavity 26 (best shown in FIG. 1A), and is generallydefined by a trailing portion 28, an intermediate shell portion 30, anda leading portion 32. Details on the various components are providedbelow. In general terms, however, the base 24 extends from the trailingportion 28 and is configured to establish a fluid connection between annCPAP generator (shown at 150 in FIG. 7A) and the cavity 26. Thetrailing portion 28 forms a bellows segment 34 (referenced generally)adapted to permit and facilitate lateral pivoting and swiveling of theintermediate shell portion 30 relative to the base 24, as well as acushioning effect whereby the bellows segment 34 can longitudinallycompress. The leading portion 32, in turn, is configured for placementabout and over a patient's nose (not shown). With this configuration,the mask 20 readily accommodates any slight misalignments uponsecurement to the patient, whereby the shell portion 30/leading portion32 effectively “float” relative to the base 24. As described below, insome embodiments, the mask 20 incorporates additional features thatfurther reduce possible patient discomfort. As used throughout thespecification, directional terminology such as “proximal” and “distal”are used with reference to a position of the mask 20 relative to apatient to whom the mask 20 is applied. Thus, “proximal” is closer tothe patient as compared to “distal”.

The mask 20 is preferably an integral, homogenous structure, formed of asurgically safe, compliant material capable of achieving a fluid sealwhen applied to a patient's skin. For example, in one embodiment, themask 20 is a molded silicone part. Alternatively, other materials suchas soft vinyls, thermoplastic elastomers, etc., are also acceptable. Inalternative embodiments, the mask 20 can have other forms, such as agel-filled or air-filled bladder configuration. However, reference tocertain dimensional attributes in the following discussion relates toone embodiment in which the mask 20, and in particular, the mask body22, is a homogenous, thin-walled structure formed of silicon orsilicone-like material.

In one embodiment, the mask body 22 includes a side wall that forms theportions 28-32 as a continuous structure that collectively define theinternal cavity 26. With this in mind, FIG. 2 depicts a side wall 40defining the trailing portion 28 as including a first section 42 and asecond section 44 in longitudinal, proximal extension from the base 24,with the sections 42, 44 combining to form the bellows segment 34. As apoint of reference, the base 24 generally defines a central axis C (FIG.2) in longitudinal extension from the mask body 22. With this conventionin mind, the first section 42 tapers inwardly relative to the centralaxis C in longitudinal (proximal) extension from the base 24, defining afirst bend 46. In other words, a transverse cross-sectional area of thecavity 26 (i.e., perpendicular to the view of FIG. 2) decreases withlongitudinal (proximal) extension of the first section 42 from the base24. Conversely, the second section 44 projects laterally outwardlyrelative to the central axis C in longitudinal (proximal) extension fromthe first section 42, with the first and second sections 42, 44combining to define a second bend 48. That is to say, the transversecross-sectional area of the cavity 26 increases along the second section44 in longitudinal (proximal) extension from the first section 42 to theintermediate shell portion 30. The first bend 46 defines a first bendangle .alpha., whereas the second bend 48 defines a second bend angle.beta.. The bend angles .alpha., .beta. can vary about a circumferenceof the mask body 22; in general terms, however, in a natural (orundeflected) state, the first bend angle .alpha. is less than 90.degree.and the second bend angle .beta. is greater than 180.degree.. With thisconstruction, the intermediate shell portion 30 can readily pivot andswivel relative to the base 24 via the bellows segment 34. For example,the intermediate shell portion 30 can pivot relative to the base 24 bycompression of the bellows segment 34 along one side thereof andexpansion of the bellows segment 34 at an opposite side. Further, theintermediate shell portion 30 can move longitudinally (distally) towardthe base 24 (i.e., rightward relative to the view of FIG. 2) viacompression of the bellows segment 34 primarily at or along the secondbend 48 (compression may also occur at or along the first bend 46 insome embodiments). While the bellows segment 34 has been shown asincluding two of the bends 46, 48, in other embodiments, only one bendis formed (e.g., the first bend 46 can be eliminated); conversely, threeor more bends can be provided in alternative embodiments.

To further enhance the flexibility afforded by the bellows segment 34,in one embodiment, at least a portion of the trailing portion 28 ischaracterized by a reduced thickness of the side wall 40 as compared toa thickness of the side wall 40 along the intermediate shell portion 30.For example and as shown in FIG. 2, in one embodiment an entirety of thefirst section 42 is characterized by a relatively uniform side wall 40thickness, whereas the side wall 40 along the second section 44 has anincreasing cross-sectional thickness in longitudinal, proximal extensionfrom the first section 42 to the intermediate shell portion 30.Regardless, in one embodiment, at least a portion of the bellows segment34, for example the first section 42, has a wall thickness that is atleast 25% less than a maximum wall thickness of the intermediate shellportion 30. Alternatively, other dimensions and/or thicknessrelationships are acceptable. Regardless, by forming at least a portionof the trailing portion 28 to have a reduced wall thickness, an overallflexibility of the bellows segment 34 is enhanced, yet the intermediateshell portion 30 is provided with sufficient structural strength andrigidity to maintain the mask body 22 (and thus a majority of the cavity26) in a desired shape during the delivery of CPAP therapy.

One or both of the bends 46, 48 and/or the reduced wall thicknessdescribed above renders the bellows segment 34 to have an increasedlateral and longitudinal flexibility as compared to lateral andlongitudinal flexibility of the intermediate shell portion 30. Infurther embodiments, one or both of the features allows the intermediateshell portion 30 to be laterally pivotable relative to the base 24 (andvice-versa) in a multiplicity of directions. To this end, in otheralternative embodiments, the mask 20 can incorporate additionalstructural features/components that further enhance lateral pivotingand/or longitudinal flexibility of the intermediate shell portion 30relative to the base 24 (and vice-versa).

As shown in FIGS. 1A and 1B, the intermediate shell portion 30 generallyexpands in outer dimension in proximal, longitudinal extension from thetrailing portion 28 to the leading portion 32. Relative to a frontplanar view (FIG. 3) of the mask 20, the intermediate shell portion 30generates a generally triangular-like exterior shape that in turn isreflected by a shape of the internal cavity 26. This triangular-likeshape corresponds with human nasal anatomy, with the intermediate shellportion 30 defining a maximum height and width of the mask body 22 at oradjacent the leading portion 32. To this end, an overall size of theintermediate shell portion 30, and thus the internal cavity 26, isconducive for use with infant patients, yet is relatively small (andthus less obtrusive to an infant patient). For example, in oneembodiment, the intermediate shell portion 30 defines a maximum heightin the range of 0.5-1.25 inches and a maximum width in the range of0.8-1.4 inches, although other dimensions are also acceptable. Notably,to better promote desired positioning of the nCPAP generator (not shown)relative to a patient during use, in one embodiment the intermediateshell portion 30 is not laterally centered relative the central axis C(FIG. 2) defined by the base 24. This off-set relationship is reflectedin FIG. 2. Alternatively, however, the intermediate shell portion 30 andthe base 24 can be more closely aligned. Finally, the intermediate shellportion 30 has various contours along the exterior surface thereof,several of which are continued by the leading portion 32 as describedbelow.

With specific references to FIGS. 2 and 3, the leading portion 32extends from the intermediate shell portion 30 (FIG. 2) and generallyincludes a distal segment 60 and a proximal segment 62 (the segments 60,62 being referenced generally in FIG. 3). The distal segment 60 extendsin a generally longitudinal (proximal) fashion from the intermediateshell portion 30, whereas the proximal segment 62 extends from thedistal segment 60 in a generally lateral fashion (i.e., inwardlyrelative to the central axis C), and terminates at a leading edge 64.The leading edge 64 defines an aperture 66 that is otherwise open to thecavity 26. To this end, the proximal segment 62 defines a patientcontact face 68 (referenced generally) that otherwise contacts thepatient (not shown) during use, with the patient's nose (not shown)extending through the aperture 66 and into the cavity 26.

With the above conventions in mind, in one embodiment at least theproximal segment 62, and preferably both the distal segment 60 and theproximal segment 62, are characterized by a decreased wall thickness ascompared to that of the intermediate shell portion 30. This relationshipis best shown in FIG. 2. The side wall 40 decreases in nominal thicknessfrom the intermediate shell portion 30 to the distal segment 60, withthis decreased thickness being maintained along an entirety of theproximal segment 62. By way of example, in one embodiment, a nominalwall thickness of the proximal segment 62 is at least 25% less than amaximum wall thickness of the intermediate shell portion 30. At least aportion of the distal segment 60 immediately adjacent the proximalsegment 62 is similarly configured in terms of wall thickness. Further,a transition of the distal segment 60 to the proximal segment 62 isrounded or arcuate in transverse cross-section, thus reducing patientdiscomfort when in contact with the patient's face as well as promotingcompliant, inward (distal) orientation of the proximal segment 62relative to the distal segment 60. One or both of these preferredfeatures render the proximal segment 62 highly flexible and compliant(as compared to the intermediate shell portion 30), thus allowing thepatient contact face 68 to more readily conform to the various contourspresented by the patient's facial anatomy when the patient contact face68 is pressed against the patient (not shown). This, in turn, improvespatient comfort and reduces possible pressure points on the patient'sface that might otherwise lead to future complications. In alternativeembodiments, the leading portion 32 need not have a differing wallthickness as compared to the intermediate shell portion 30.

In addition to, in one embodiment, being flexible and compliant, theleading portion 32, and in particular the proximal segment 62, ispreferably sized and shaped to more closely match expected anatomicalcharacteristics of the patient's face (not shown). For example, withspecific reference to FIG. 3, relative to a frontal planar view of themask body 22, the proximal segment 62, and in particular the patientcontact face 68, generally defines or forms a lip region 80, first andsecond side regions 82, 84, and a bridge region 86. The side regions 82,84 extend from opposite ends, respectively, of the lip region 80.Further, the side regions 82, 84 connect at the bridge region 86, thatis otherwise formed opposite the lip region 80. The regions 80-86combine to define a triangular-like shape. To this end, a perimeter 88of each of the side regions 82, 84 forms an ocular relief feature orcontour 90 (referenced generally). More particularly, the perimeter 88of each of the side regions 82, 84 defines the ocular relief feature 90as a concave curvature in extension from the lip region 80 to the bridgeregion 86 relative to a frontal plane or view of the mask body 22. Theocular relief feature 90 reduces or even eliminates the potential ofpushing the patient's skin into or toward the patient's eye as the mask20 is pressed against the patient's face, thus enhancing patientcomfort.

To better ensure the elimination of air leaks around the patient's eyes,in one embodiment, the side regions 82, 84 have a fairly large width(i.e., lateral distance from the perimeter 88 to the leading edge 64)and further include or define a longitudinal (proximal) projection orcontour that better matches the anatomical shape of the patient's facein a region between the nose and the eye. This relationship is bestshown in the longitudinal cross-sectional view of FIG. 2 in which theside region 82 is illustrated as having a convex curvature feature 92(i.e., longitudinally outward or proximal extension or projectionrelative to the intermediate shell portion 30) adjacent the bridgeregion 86. Alternatively, especially where the mask 20 is configured foruse with very small infants, the convex curvature feature 92 can bereduced or eliminated.

Returning to FIG. 3, the lip region 80 is, in some embodiments,contoured to better match expected anatomical features of the patient,and in particular the patient's lip (e.g., region of the upper lipbetween the vermilion border and the nose, including the philtrum). Forexample, in one embodiment, the lip region 80 has a distal or inwardcurvature (best shown in FIG. 1A and also in FIG. 4) to anatomicallymatch a protrusion of the patient's philtrum. In addition, in oneembodiment, the lip region 80 defines a septal relief feature 100. Theseptal relief feature 100 is best shown in FIG. 3 and is characterizedby the lip region 80 defining a convex lateral curvature in extensionbetween the side regions 82, 84. That is to say, the lip region 80projects or curves laterally outwardly or downwardly (relative to theupright orientation of FIG. 3) in extension between the side regions 82,84. The septal relief feature 100 minimizes overt contact (andpreferably eliminates any contact) between the lip region 80 and thepatient's upper lip in the region adjacent the nasal septum (e.g., thephiltrum skin) during use, thus minimizing opportunities for skinbreakdown in this delicate area and increasing patient comfort.

In one embodiment, the mask body 22 includes all of the features 90, 92and 100 described above. In alternative embodiments, one or more of thecontour features 90, 92 and/or 100 can be altered or eliminated.

An additional feature of the mask body 22 in accordance with someembodiments of the present invention is further illustrated in FIG. 4.More particularly, in one embodiment, the intermediate shell portion 30defines or forms a viewing window 110 (illustrated schematically) alonga bottom face 112 thereof. As a point of reference, an overall,generally triangular shape of the mask body 22 dictates a desiredorientation when applied over a patient's nose (not shown). Moreparticularly, and with additional reference to FIG. 1A, the mask body 22is sized and shaped to be secured over the patient's nose in the uprightorientation shown. In conjunction with this upright orientation, then,the intermediate shell portion 30 thus defines a top face 114 and thebottom face 112. When applied over a patient's nose, the top face 114 isproximate a bridge of the patient's nose, whereas the bottom face 112 isproximate (below) the patient's nasal septum/philtrum. With theseconventions in mind, and returning to FIG. 4, the viewing window 110facilitates viewing of the patient's nares and/or nasal septum once themask body 22 is applied over the patient's nose. The viewing window 110can assume a variety of forms, but does not negatively affect an abilityof the mask body 22 to establish a fluid-tight seal over the patient'sfacial anatomy/nasal airways. Further, the viewing window 110 preferablydoes not negatively affect an overall structural rigidity of theintermediate shell portion 30. With these constraints in mind, in oneembodiment, the viewing window 110 is formed and characterized asexhibiting an opacity that is less than an opacity of a remainder of theintermediate shell portion 30. For example, in one embodiment, the maskbody 22, preferably an entirety of the mask 20, is integrally andhomogeneously formed as a continuous, molded part comprising a siliconeplastic. With this in mind, the mold from which the mask body 22 isformed can be highly polished in the region corresponding to the viewingwindow 110, thus decreasing an opacity of the intermediate shell portion30 at the viewing window 110 as compared to a remainder of theintermediate shell portion 30. Alternatively, the viewing window 110 canbe formed in a variety of other ways, and can be formed at one or morelocations in addition to, or instead of, the bottom face 112. Evenfurther, in other embodiments, the viewing window 110 is eliminated.

With reference to FIGS. 5 and 6, the base 24 extends from the trailingportion 28 and in one embodiment forms first and second passages 120,122, and a channel 124. The passages 120, 122 extend in a longitudinalfashion (e.g., parallel with the base central axis C) through athickness of the base 24, and are fluidly connected to the cavity 26 asshown best in FIG. 6. As described in greater detail below, the passages120, 122 are sized for assembly over corresponding components of a CPAPgenerator device (shown at 150 in FIG. 7A), and thus are open relativeto a rear face 126 of the base 24. Thus, the passages 120, 122 provide amechanism for fluidly connecting the CPAP generator device to the cavity26. The channel 124 extends between, and is fluidly connected to, thepassages 120, 122. In addition, while the channel 124 is open at therear face 126, the channel 124 is not directly fluidly connected to thecavity 26. As described in greater detail below, the channel 124 issized and shaped in accordance with certain features of one embodimentCPAP generator device, and facilitates sampling or tapping of pressurewithin the device. Thus, the channel 124 can assume a wide variety offorms. In fact, in some embodiments, the channel 124 is eliminated.Similarly, while two of the passages 120, 122 are shown, in otherembodiments, the base 24 can form only one, or more than two, of thepassages 120, 122.

With specific reference to FIG. 5, the base 24 is, in one embodiment,sized and shaped for interfacing with a corresponding component of aCPAP generator device (shown at 150 in FIG. 7A) and fluidly connectingthe passage(s) 120 and/or 122 to the CPAP generator device. In thisregard, an exterior of the base 24 defines a perimeter 130 (best shownin FIG. 5) that includes opposing first and second side edges 132, 134and opposing, first and second end edges 136, 138. In one embodiment, anintersection or transition of the first side edge 132 to each of the endedges 136, 138 differs from the transition or intersection of the secondside edge 134 to the end edges 136, 138. For example, in one embodiment,transition of the second side edge 134 to each of the end edges 136, 138is characterized as being arcuate or curved, having a relatively largeradius of curvature. In contrast, a transition of the first side edge132 to each of the end edges 136, 138 is characterized as defining arelatively distinct corner, having a radius curvature that is less thanthat of the second side edge 134/end edge 136, 138 transitions. Thus, alateral length of the first side edge 132 is greater than that of thesecond side edge 134. This one preferred configuration of the perimeter130 corresponds with feature(s) of the CPAP generator device so as toensure a desired, proper orientation of the base 24, and thus the maskbody 22, relative to the CPAP generator device upon final assembly.

For example, FIG. 7A illustrates a portion of one embodiment CPAPgenerator device 150 with which the mask 20 is useful in accordance withprinciples of the present invention. Details on embodiments of the CPAPdevice 150 are provided in U.S. Pat. No. 7,578,294 entitled “NasalContinuous Positive Airway Pressure Device and System,” issued on Aug.25, 2009, the teachings of which are incorporated herein by reference.In general terms, the CPAP device 150 includes first and second tubes152, 154 laterally surrounded by a housing 156. During use, the CPAPdevice 150 generates a continuous positive airway pressure within eachof the tubes 152, 154. With these general concepts in mind, the passages120, 122 of the base 24 are sized for mating over a respective one ofthe tubes 152, 154, and the base 24 received and frictionally retainedwithin the housing 156. In this regard, an internal perimeter shape ofthe housing 156 corresponds with the perimeter 130 of the base 24 aspreviously described.

In particular, the differing lengths of the side edges 132, 134, as wellas the curved and corner-shaped transition regions previously describedprevents a user from accidentally attempting to insert the base 24 intothe housing 156 in an orientation opposite to that desired (i.e., theupright orientation). That is to say, the base 24/housing 156 interfacepermits only one orientation of the base 24, and thus of the mask 20,relative to the CPAP device 150.

FIG. 7B partially illustrates assembly of the base 24 to the CPAP device150, and in particular, the first passage 120 over the first tube 152and the second passage 122 over the second tube 154. As shown, each ofthe tubes 152, 154 includes a radial slot 158 that is otherwise fluidlyconnected to the channel 124 upon final assembly of the base 24 withinthe housing 156. With this one arrangement, then, airflow within thetube 154 is allowed to flow from the tube 154/base 24 interface, via thechannel 124, for subsequent pressure monitoring. In one embodiment adepth and width of the channel 124 is correlated with a diameter of thepassages 120, 122 to minimize formation of back pressure within thedevice 20 during delivery of CPAP therapy while still affording theability to accurately sample pressure being delivered to the patient. Tothis end, it has surprisingly been found that by forming the channel 124to have a depth that is at least 30% of the diameter of either passage120, 122 and a width that is at least 25% of either passage 120, 122diameter, significant back pressure will not be generated at expectedCPAP levels.

Although the mask 20 has been described in connection with certainfeatures of the CPAP device 150, a wide variety of differing CPAP deviceconfigurations can also be employed. That is to say, the mask 20 inaccordance with principles of the present invention is not limited toany one particular CPAP device design.

The infant nasal interface mask in accordance with principles of thepresent invention provides a marked improvement over previous designs.The thin-walled, bellows segment allows the shell/patient face of themask to easily pivot and/or flex relative to the base (and thus the CPAPgenerator to which the base is assembled). This attribute allows themask to accommodate any misalignments of the CPAP generator and/orrelated fixation device relative to the patient, and further minimizesor eliminates pressure point(s) on the infant's/patient's nose or facethat might otherwise be created by CPAP generator misalignment. Othermask features in accordance with alternative embodiments further promotepatient comfort and assembly to, and operation of, the CPAP generator.For example, an alternative embodiment infant nasal interface mask 20′is shown in FIG. 8, and is similar in many respects to the mask 20 (FIG.1A) previously described. Thus, the mask 20′ includes a mask body 22′and a base 24, with the mask body 22′ forming a bellows segment 34′. Thebellows segment 34′ is similar to previous embodiments, and includesfirst and second wall sections 42′, 44′, as well as one or more ribs200. The rib(s) 200 project laterally outwardly along one or both of thewall sections 42′, 44′, and provide a tactile indication to auser/physician that the bellows segment 34′ has been overtly compressedor collapsed, a condition that might otherwise lead to airflow exchangecomplications. For example, the ribs 200 resist further contraction ofthe bellows segment 34′ as the second section 44′ contacts the ribs 200,and can even “force” the bellows segment 34′ to revert back toward anuncompressed state.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A nasal interface mask, comprising: a mask bodycomprising a sidewall that defines a cavity in the mask body; and a basecomprising a pair of passages extending through a thickness of the baseand a channel extending between the pair of passages, the base defininga central axis, wherein the sidewall of the mask body extends from thebase to form a first section and a second section in longitudinal,proximal extension from the base to form a bellows segment, wherein thefirst section tapers inwardly relative to the central axis inlongitudinal extension from the base thereby defining a first bend inthe sidewall, and wherein the second section tapers outwardly relativeto the central axis in longitudinal extension from the first section sothat the first section and the second section combine to define a secondbend in the sidewall.
 2. The nasal interface mask of claim 1, whereinthe first bend has a first bend angle that is smaller than a second bendangle of the second bend.
 3. The nasal interface mask of claim 2,wherein the first bend angle is less than ninety degrees and the secondbend angle is greater than 180 degrees.
 4. The nasal interface mask ofclaim 1, wherein the pair of passages is permanently fluidly open to thecavity.
 5. The nasal interface mask of claim 1, wherein the mask bodyfurther comprises a patient contact face comprising a lip region, firstand second side regions, and a bridge region, wherein the first andsecond side regions extend from opposite ends, respectively, of the lipregion and connect at the bridge region.
 6. The nasal interface mask ofclaim 5, wherein the bridge region is disposed opposite the lip regionso that the lip region, the first and second side regions, and thebridge region combine to define a triangular shape.
 7. The nasalinterface mask of claim 6, wherein a perimeter of each of the first andsecond side regions has a concave curvature in extension from the lipregion to the bridge region to form respective first and second ocularrelief features.
 8. The nasal interface mask of claim 1, furthercomprising a plurality of ribs that each extend laterally along thefirst section.
 9. The nasal interface mask of claim 1, wherein the pairof passages extend through a thickness of the base in a direction thatis parallel with the central axis.
 10. A device, comprising: a nasalinterface mask, comprising: a mask body comprising a sidewall thatdefines a cavity in the mask body; and a base comprising a pair ofpassages extending through a thickness of the base and a channelextending between the pair of passages, the base defining a centralaxis, wherein the sidewall of the mask body extends from the base toform a first section and a second section in longitudinal, proximalextension from the base to form a bellows segment, wherein the firstsection tapers inwardly relative to the central axis in longitudinalextension from the base thereby defining a first bend in the sidewall,and wherein the second section tapers outwardly relative to the centralaxis in longitudinal extension from the first section so that the firstsection and the second section combine to define a second bend in thesidewall; and a generator having a housing configured to receive thebase.
 11. The device of claim 10, wherein the pair of passages ispermanently fluidly open to the cavity.
 12. The device of claim 10,wherein the generator comprises a pair of tubes fluidly connected to afluid supply port, the generator adapted to generate a continuouspositive airway pressure within each of the pair of tubes.
 13. Thedevice of claim 12, wherein each of the pair of passages in the base areconfigured to mate with a corresponding one of the pair of tubes in thegenerator.
 14. The device of claim 12, wherein each of the pair of tubescomprises a radial slot configured to be fluidly connected to thechannel.
 15. The device of claim 10 wherein the sidewall along the firstsection comprises a uniform sidewall thickness.
 16. The device of claim15, wherein the sidewall along the second section has an increasingcross-sectional thickness in longitudinal, proximal extension from thefirst section.
 17. The device of claim 10, wherein the channel comprisesany of a depth that is at least 30% of a diameter of either of the pairof passages, and a width that is at least 25% of a diameter of either ofthe pair of passages.
 18. A nasal interface mask, comprising: a maskbody, comprising: a cavity; a patient contact face having an aperturethat is open to the cavity and having a generally triangular shape; anintermediate portion, the patient contact face having a reduced wallthickness as compared to a nominal wall thickness of the intermediateportion and defining opposing ocular reliefs and a septal relieffeature; and a bellows segment having a reduced wall thickness ascompared to a nominal wall thickness of the intermediate portion, andforming a bend in longitudinal extension, wherein the intermediateportion is disposed between the patient contact face and the bellowssegment; and a base extending from the bellows segment opposite theintermediate portion, the base forming a pair of passages that extendlongitudinally through a thickness of the base and a channel extendingbetween the pair of passages, wherein the pair of passages are fluidlyconnected to the cavity, and the intermediate portion is laterallypivotable relative to the base via the bellows segment.
 19. The nasalinterface mask of claim 18, wherein the bellows segment includes asidewall that defines a first section extending generally longitudinallyfrom the base and a second section extending generally longitudinallyfrom the first section toward the intermediate portion, and wherein thefirst section forms the cavity to have a proximally decreasingtransverse cross-sectional area to define the bend relative to the base,and the second section forms the cavity to have a proximally increasingtransverse cross-sectional area to define a second bend relative to thefirst section.
 20. The nasal interface mask of claim 19, wherein thebend has a first bend angle that is smaller than a second bend angle ofthe second bend.